Many industrial applications require two or more independent optical images of different wavelengths or colors to be simultaneously projected onto the same specimen. As an example, in optogenetics research, a blue image can be used to excite certain neurons while an orange or red image can be used to silence some other neurons.
In general, a spatial light modulator (“SLM”) may be used to generate an image to be projected onto a specimen. One conventional solution is to use multiple SLMs, where each generates an image of a single color, and then combine the images into a single image. An example of such a system is a three-panel color projector for display applications.
However, the use of a system having multiple SLMs has several drawbacks. Such system is expensive and requires a complex optical layout arrangement. Also, it is not particularly suitable for applications requiring a space-efficient compact design.